Field of the Invention
The present invention relates to a differential signal driving circuit for signal transmission in low voltage differential signaling (LVDS).
Description of the Related Art
In LVDS transmission, Japanese Patent Laid-Open No. 2007-134940 discloses a differential signal driving circuit provided with a common feedback (hereinafter, CMFB) circuit for realizing good signal transmission. According to this Patent Document, a capacitor is inserted between a gate and a drain of an MOS transistor functioning as a current source, so that the phase margin at the pole of the transfer function is improved. However, as the external load capacitance of a transmission line increases, the position of the pole shifts toward the low frequency range. At that time, if the position of the pole is lowered to a frequency range corresponding to at least one time the amplitude gain of the open-loop transfer function of the CMFB circuit, the driving circuit may not have enough phase margin.